1. Field of the Invention
This invention relates to a liquid crystal projection color display apparatus in which an optical image formed through a liquid crystal display device is illuminated by an illuminating light thereby projecting it through a projection lens on a screen.
2. Description of the Prior Art
Conventionally, a liquid crystal projection display apparatus having a microlens array arranged on the lightsource side of a liquid crystal display device, in which an optical image to be formed is illuminated by pixel through the microlens array by an illuminating light and expandably projected through a projection lens onto a screen (see, for example, Japanese Laid-Open Patent Application No. 1-189685 (1989). FIGS. 5A-5B schematically exemplify a liquid crystal projection display apparatus of this type. In FIGS. 5A-5B, element 41 is a light source element 42 is a condenser lens; element 43 is a liquid crystal display device; element 44 is a projection lens and element 45 is a screen. The liquid crystal display device 43 is illustrated in detail in the circle shown in FIG. 5B, which comprises a polarizer plate 46, a microlens array 47, a liquid crystal display panel 48 and a polarizer plate 49. The microlens array 44 has a plurality of microlenses each having a positive refractive power arranged in a matrix. An incident light inputted to the liquid crystal display panel 43 is made into a linearly polarized light through the polarizer plate 46, then condensed through the microlens array 47 subdivisibly on each of pixels arranged in a matrix of the liquid crystal display panel 48 and passes through the liquid crystal display panel 48. In this case, each light beam is expanded while being polarized by the liquid crystal display panel 48 and an optically modulated light passes through the polarizer plate 49. An output light from the liquid crystal display panel 43 is expanded through the projection lens 44 and sent to the screen 45 to project an image thereon. With this apparatus, a light once condensed through the microlens array 47 subdivisibly on each pixel of the liquid crystal display device 48 goes to the projection lens 44 while being subjected to divergence. The light thus divergently entering the projection lens 44 is expansibly outputted therefrom. As a result, if the distance between a liquid crystal display device and a projection lens exceeds a specific value, then signals of pixels adjacent to each other can be mixed systematically, resulting in adverse effects on a systematic basis. In addition, in case of the color display apparatus, images of three primary color light beams of red (R), green (G) and blue (B), must have an integrally identical magnification ratio. With the conventional technology, however, it is disadvantageously difficult to overcome such a problem.